Techniques for delivery of stem cell and related therapies to treat cardiac conditions

ABSTRACT

An exemplary method includes acquiring cardiac electrical activity information; detecting an R wave; and based on the detecting, calling for delivery of energy to cells located in a structure outside of the myocardium only during a period time within the QRS complex corresponding to the detected R wave. The energy delivered may be electrical stimulation energy or mechanical energy.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of copending U.S. patent application Ser.No. 11/556,631, filed Nov. 3, 2006, titled “Techniques for Delivery ofStem Cell and Related Therapies to Treat Cardiac Conditions” and isrelated to U.S. patent application Ser. No. ______ (Attorney Docket No.A06P1118US01), filed currently herewith, titled “Techniques for Deliveryof Stem Cell and Related Therapies to Treat Cardiac Conditions” and U.S.patent application Ser. No. ______ (Attorney Docket No. A06P1118US03),filed currently herewith, titled “Techniques for Delivery of Stem Celland Related Therapies to Treat Cardiac Conditions.”

TECHNICAL FIELD

Subject matter presented herein relates generally to stem cell andrelated therapies. More specifically, various techniques pertain to useof cardiac electrical activity and other physiological information toenhance such therapies.

BACKGROUND

Various studies report use of stem cell and related therapies forimproving cardiac performance. Proposed mechanisms include passiveeffects on scar tissue, neovascularization leading to reducedcardiomyocyte apoptosis, cell fusion and paracrine effects leading toproliferation of endogenous cardiomyocytes and cardiomyocyteregeneration as well as transdifferentiation leading to cardiomyocyteregeneration. While some view a lack of understanding as to specificmechanisms by which stem cell and related therapies improve cardiacperformance, various processes have nevertheless been identified asbeing beneficial to such therapies. For example, many therapies includeprocesses such as conditioning cells with electrical stimuli, injectingcells into the body, feeding cells, etc. With respect to applyingelectrical stimuli, various studies indicate that such conditioning canreduce myocardial heterogeneity (e.g., electrical and/or structural),which may cause paroxysmal arrhythmia.

Some studies advocate in vivo conditioning while others report that invivo conditioning is not required. For example, a study by Yang et al.,“Rapid stimulation causes electrical remodeling in cultured atrialmyocytes”, J Mol Cell Cardiol. 2005 February; 38(2):299-308, reportedthat rapid stimulation of atrial cells in culture produces electricalremodeling and that in vivo conditions are not required for thedevelopment of electrical remodeling. Another study by Park, “Electricalstimulation enhances the expression of cardiac properties in 3-Dcultured cells”, reported that application of electrical stimulationduring cell culture in three-dimensional scaffolds enhanced both thecardiac differentiation of mesenchymal stem cells and the functionalassembly of cardiomyocytes into contractile tissue constructs.

Various exemplary technologies described herein pertain to stem cell andrelated therapies. For example, various technologies may mimic orreproduce biological conditions and/or mimic or reproduce therapeuticconditions to enhance stem cell or related therapies.

SUMMARY

An exemplary method includes acquiring cardiac electrical activityinformation, detecting a T wave and, based on the detecting, calling fordelivery of matter to the heart where the matter may include one or moreof stem cells, progenitor cells, nutrients and drugs. Another exemplarymethod includes calling for delivery of electrical energy to cellsdestined for implantation in the body or cells already implanted in thebody. Such delivery may be timed according to cardiac electricalactivity and/or delivered at an energy level below a capture thresholdof neighboring tissue. Various other exemplary technologies are alsodisclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the described implementations can be morereadily understood by reference to the following description taken inconjunction with the accompanying drawings.

FIG. 1 is a diagram of two convention methods for treating the heartusing stem cells or progenitor cells.

FIG. 2 is a diagram of an exemplary device and various exemplary leadsfor use in stem cell or related therapies.

FIG. 3 is a diagram of various cell related actions and timing and/orcoordination information for use in control of such actions.

FIG. 4 is a diagram of three scenarios for cell related actions wherecells may be in a reservoir in the body or external to the body or wherecells may be in the body.

FIG. 5 is a diagram of an exemplary scenario for activating a pump todeliver matter based at least in part on ECG and/or EGM information.

FIG. 6 is an ECG that illustrates various features associated withcardiac activity or cardiac condition.

FIG. 7 is a diagram of an exemplary scenario for conditioning cellsbased at least in part on ECG and/or EGM information.

FIG. 8 is a diagram of an exemplary scenario for mechanicallyconditioning cells based at least in part on ECG and/or EGM information.

FIG. 9 is a diagram of an exemplary method for conditioning cells anddeciding whether cells have been adequately conditioned.

FIG. 10 is a diagram of an exemplary method for delivering matter basedat least in part on physiological information.

FIG. 11 is a diagram of an exemplary method for delivering cardiacpacing therapy and cell conditioning, based at least in part on acapture threshold.

DETAILED DESCRIPTION

FIG. 1 shows two methods 110, 120 of treating a damaged region of theheart. The method 110 involves injection of cells to the heart. In thisexample, the cells may be stem cells, stem cells plus one or morechemicals or progenitor cells. Stem cells have both the capacity toself-renew (make more stem cells by cell division) as well as todifferentiate into mature, specialized cells. A progenitor cell is anearly descendant of a stem cell that can only differentiate, but itcannot renew itself anymore. In contrast, a stem cell can renew itself(make more stem cells by cell division) or it can differentiate (divideand with each cell division evolve more and more into different types ofcells). A progenitor cell is often more limited in the kinds of cells itcan become than a stem cell and hence more differentiated than a stemcell. Addition of a chemical to a stem cell may generate a progenitorcell.

The method 120 involves injection of one or more chemicals to the heart.The chemical(s) may act to generate progenitor cells or otherwisegenerate myocytes and/or vascular structures.

Whether repair occurs via injection of cells or via injection of one ormore chemicals, cells or generated cells must be integrated into theheart and “learn” to function properly. Cardiac cells that beat in acell culture, for example, may not beat in rhythm with a patient's ownheart cells. And neurons injected into a damaged neural pathway mustbecome “wired” into the pathway's intricate network of cells to connectand work properly. Further, tissue rejection should be avoided. Just asin organ transplants, immune cells may recognize transplanted cells asforeign and set off an immune reaction. Cell recipients may be advisedto use of drugs to at least temporarily suppress their immune systems.

FIG. 2 shows a block diagram of an exemplary device capable ofperforming any of a variety of actions including actions of the method110 and the method 120. A basic device may include a processor, memory,one or more inputs, one or more outputs and control logic stored asinstructions in the memory and operable in conjunction with theprocessor. The device 200 includes various additional features.

The exemplary device 200 includes a programmable microprocessor 210 thatcan implement control logic 230 and other instructional modules 234.Information may be stored in memory 224 and accessed by the programmablemicroprocessor 210. For delivery of electrical energy, the device 200includes one or more pulse generators 242, 244. The pulse generators242, 244 may rely on a switch 220 for delivery of energy via one or moreconnectors 225. While a device may include one or more integral leads,in general, a device includes one or more connectors for connecting alead or leads to the device. More particularly, the connectors 225provide for electrically connecting one or more electrodes to thecircuitry of the device 200. In the example of FIG. 2, the switch 220may select an appropriate electrode configuration. An electrodeconfiguration may include an electrode from one lead and an electrodefrom another lead, a case electrode and another electrode or electrodesfrom a single lead.

The device 200 further includes one or more analog to digital converters252, 254 for converting analog signals to digital signals or values. Theprocessor 210 may use a signal provided by one of the ND converters 252,254 to control a therapy or other process. A control signal from theprocessor 210 may instruct the switch 220 to select a particularelectrode configuration for sensing electrical or other activity. Asdiscussed below, various techniques include sensing nerve activity orother activity.

The device may include one or more physiological sensors 260. Suchsensors may be housed within a case of the device 200 (e.g., a motionsensor), include a surface mounted component, include a lead, include aremote sensor, etc. A sensor may provide a digital signal or an analogsignal for use by the processor 210 or other circuitry of the device200. A physiological sensor may provide a signal via one or more of theconnectors 225.

For purposes of communication with external or other implantabledevices, the device 200 includes a telemetry circuit 270. The telemetrycircuit 270 may include one or more antennae for transmission and/orreceipt of electromagnetic signals. Such a circuit may operate accordingto a specialized frequency or frequencies designated for medicaldevices. Various conventional implantable devices rely on an associatedprogrammer, which is an typically an external computing device with acommunication circuit suitable for communicating with an implantabledevice for purposes of data transfer, status checks, software download,etc. Where the circuit 270 communicates with an implantable device or adevice in electrical connection with a patient's body, then the body maybe a conductive medium for transfer of information. For example, thecircuit 270 may be capable of communication with a specializedwristwatch where the body is relied upon as a conductor.

The device 200 further includes an impedance measuring circuit 274. Sucha circuit may rely on instructions from the processor 210. For example,the processor 210 may instruct the circuit 274 to provide a measuredimpedance for a particular electrode configuration. In such an example,the processor 210 may also instruct the switch 220 to provide thecircuit 274 with a particular electrode configuration. Impedanceinformation may be used by the processor 210 for any of a variety ofpurposes. The processor 210 may store impedance or other information tomemory 224 for later use or for transmission via the telemetry circuit270.

The device 200 includes a power source, which is shown as a batter 280in the example of FIG. 2. The battery 280 powers the processor 210 andoptionally other circuitry, as appropriate. In general, the battery 280provides power to the pulse generators 242, 244. Consequently, thebattery 280 provides for operation of circuitry for processing controllogic, etc., and provides for energy to activate tissue. A lead-basedsensor may connect to the device 200 via one or more of the connectors225 and be powered by the battery 280. The battery 280 may berechargeable, replaceable, etc.

The device 200 includes a cell reservoir 290 and an associated accessport 291, which may allow for insertion of a needle or other instrument.Where the device 200 is an implantable device, the port 291 may allowfor transdermal access to the reservoir 290. A nutrient reservoir 292includes an associated access port 292, which may similarly for accessto the nutrient reservoir 292. A pump 295 may also include an accessport 296. For example, injection of a chemical into the port may allowthe pump 295 to pump the chemical to one or more locations.

The cell reservoir 290 may include cells attached to and/or containedwithin a cell carrier. For example, microspheres may be used to carriercells. Such microspheres may degrade in the body and may providenutrients for cell growth and/or chemicals for cell action (e.g.,differentiation of stem cells).

The device 200 further includes a connector 297 for connecting a conduitor lead 205. In the example of FIG. 2, the lead 205 includes twoelectrodes 207, 207′ disposed adjacent an opening 209. The opening 209connects to the pump 295 via the connector 297. Instructions from theprocessor 210 may cause the pump 295 to pump matter to and/or from thecell reservoir 290 and/or the nutrient reservoir 292. In an alternative,matter may be introduced or removed via the port 296. For example, thepump 295 may operate to sample fluid via the opening 209, which may thenbe extracted from the device 200 via the port 296. Where the device 200is an implantable device, the arrangement may allow sampling of fluidand/or tissue from the body of a patient. In an alternative arrangement,the lead 205 includes prongs 208 disposed between a pair of electrodes207, 207′. The prongs 208 may anchor or help anchor the lead to tissueand allow for delivery of matter at one or more depths. In anotheralternative arrangement, the lead 205 includes a screw end that includestwo or more electrodes 207, 207′ and openings 209, for example, openingoutwardly for delivery of matter (e.g., fluid, nutrients, drugs, cells,etc.).

As described in more detail below, the electrodes 207, 207′ may be usedfor any of a variety of purposes. For example, the electrodes 207, 207′may allow for sensing cardiac electrical activity, measuring impedance,delivery of stimulation energy, generation of an electro-magnetic field,etc. Where the electrodes 207, 207′ allow for sensing cardiac electricalactivity, the device 200 may act based on such information byconditioning cells, pumping cells, etc. Where the electrodes 207, 207′allow for measurement of impedance, the device 200 may act on suchinformation by deciding if matter delivered via the lead 205 is incontact with the electrodes, by deciding if the opening(s) 208 or 209are in a particular region (e.g., tissue, fluid, etc.), by deciding iffouling has occurred of the opening(s) 208 or 209, etc. Where theelectrodes 207, 207′ allow for generation of an electro-magnetic field,the device 200 may generate such a field to enhance delivery of matter(e.g., cells, nutrients, drugs, etc.).

While a single lead is shown in FIG. 2, multiple leads may be used orone or more leads configured differently than the lead 205. For example,a lead may connect to a patch where the patch affixes to the heart(e.g., a wall of the left ventricle). The patch may serve as a deliverymechanism for nutrients or drugs, may serve as a reservoir for cells,may include openings for delivery of cells and may include one or moreelectrodes for any of a variety of purposes.

With respect to flow channels or conduits of the device 200,microfluidic technologies may be employed. Microfluidic technologiesgenerally include one or more channels with at least one dimension ofless than about a few millimeters. Microfluidic technologies maytransport whole blood samples, bacterial cell suspensions, protein orantibody solutions, buffers, etc. Measurements of molecular diffusioncoefficients, fluid viscosity, pH, enzyme reaction kinetics, etc., maybe facilitated via microfluidic technologies. Other applications inmicrofluidics include capillary electrophoresis, isoelectric focusing,immunoassays, flow cytometry, cell manipulation, cell separation, cellpatterning, chemical gradient formation, etc. Many applications haveutility for clinical diagnostics.

With respect to pumping of matter, any of a variety of techniques may beused. For example, a pressure source (e.g., piezoelectric, mechanical,compressed gas, chemical, etc.), a mechanical pump, electrokineticmechanisms, osmotic, electro-osmotic, etc., may be used. An exemplarydevice may use variations in pressure (e.g., intrapleural,intrathoracic, airway, etc.) that accompany respiration to promote flowor for pumping. For example, as the diaphragm contracts, the ribcageexpands, which causes a decrease in intrathoracic pressure and flow ofair into the lungs. With respect to intrapleural pressure, under normalconditions, it is always negative. The negative pressure between the twopleurae maintains partial lung expansion by keeping the lung pulled upagainst the chest wall. The degree of negativity, however, changesduring respiration. During inhalation, the pressure is approximately −8cm H₂O; during exhalation, approximately −4 cm H₂O. If a patient takes adeeper breath, the intrapleural pressure will be more negative. Aballoon or compliant reservoir and valve arrangement may allow suchvariations in pressure to pump matter or to assist pumping of matter.Where a device may benefit from circulating media for cells (e.g., in acell reservoir), variations in pressure may be used to promotecirculation or mixing of media to carry nutrients to cells and to removewaste products from the cells.

The switch 220 may be configured such that energy from a pulse generator242, 244 is delivered to the cell reservoir 290 in a manner controlledby the processor 210. For example, the telemetry circuit 270 may receivea signal indicative of an intrinsic heart beat or one or more electrodesmay sense cardiac electrical activity where energy is delivered to thecell reservoir based at least in part on such a signal or sensedactivity. The switch 220 may be configured to allow for impedance orother measurements of the cell reservoir 290 and optionally the nutrientreservoir 292 and/or the pump 295. For example, impedance may indicate achange in cell density in the cell reservoir 290, a change in chemicalcomposition or volume in the nutrient reservoir 292 and condition of thepump 295.

One or more of the physiological sensors 260 may be capable of sensingconditions of the cell reservoir 290, the nutrient reservoir 292 and/ormatter passing through the pump 295.

While the device 200 includes particular features, various exemplarydevices, systems, methods, etc., may use or be implemented using adifferent device or devices with more or less features. For example, onedevice may provide fluidics while another device provides information tothe fluidics device. The device 200 may include features as associatedwith an insulin or other drug delivery device.

FIG. 3 shows an exemplary scheme 300 where various cell related actions301 coordinated with various event and/or condition information 303. Theactions 301 include drug administration 310 (immune suppressant, growthfactors, etc.), nutrient feed 320, conditioning 330 and cell injection340. The information 303 includes ECG and/or EGM information 350 andother timing information 360 (e.g., as associated with variousphysiological cycles, whether intrinsic or therapy driven). As describedherein, various exemplary devices, methods, systems, etc., perform cellrelated action based at least in part on event and/or conditioninformation. For example, EGM information 350 may be used to timeinjection of cells to the heart 340 or respiration information 360 maybe used to time delivery of nutrients to the heart 320. As examples, theECG/EGM information 350 shows an ECG (a plot of electrical activity ofthe heart) while the other information 360 shows a plot of centralvenous pressure (CVP) or a pulmonary artery pressure (PAP) with A, C andV waves. A CVP/PAP A wave is associated with atrial contraction, aCVP/PAP C wave is associated with closure of the tricuspid valve and aCVP/PAP V wave is associated with ventricular contraction. The ECG orthe CVP/PAP may be used for purposes of timing actions such as deliveryof nutrients, injection of cells, etc. Further, a simultaneous ECG andCVP/PAP may be used for purposes of timing actions. In general, aCVP/PAP A wave follows an atrial event (e.g., intrinsic P wave or pacedA wave) and a CVP/PAP V wave follows a ventricular event (e.g.,intrinsic R wave or paced V wave).

FIG. 4 shows various scenarios 401, 402, 403 for stem cell or relatedcell therapy and exemplary arrangements A, B, C, D, E and F for thesetherapies. The scenario 401 pertains to treating cells 405 that areexternal to the body of a patient. According to the scenario 401,actions such as drug administration 410, feeding 420 and conditioning430 may occur. These actions may prepare the cells 405 for implantationin the body of a patient or for production of a particular chemical,which may be administered to a patient. For example, the cells 405 mayproduce a chemical that signals cell growth or growth of vascularstructures. The chemical may be harvested from a cell reservoir andinjected into a patient (e.g., myocardial injection, etc.) to therebypromote growth of myocytes, vascular structures, etc. While threeexemplary arrangements (A, B and C) are shown as associated withscenario 401, other arrangements may be possible.

In arrangement A, a patient wears a device that includes a cellreservoir. The device may be fitted to a strap, a holster, etc., and maycontact the body to help heat the cells. The device may sense patientphysiology and response by administering a drug 410 to the cells 405,feeding 420 the cells 405 and/or conditioning 430 the cells 405. Thedevice may include various features of the device 200 of FIG. 2. Thecells 405 may be destined for injection into the heart or they may beused to produce chemicals for delivery to the heart.

In arrangement B, a patient wears an external device that includes acell reservoir and the patient has an implanted device that maycommunicate information (e.g., data or a signal) to the external device.The implanted device may include features of the device 200 of FIG. 2and may be capable of delivering a pacing or other stimulation therapy(e.g., cardiac, other muscle, nerve, etc.). As explained below, theimplanted device may provide information regarding cardiac activity thatcan be used to administer a drug 410 to the cells 405, feed 420 thecells 405 and/or condition 430 the cells 405. The exemplary device 200of FIG. 2 may be used to perform such actions.

In arrangement C, a clinician examines a patient and enters informationto a controller that controls drug administration 410, feeding 420and/or conditioning of the cells 405, which may be housed in a devicesuch as an incubator. The clinician may have access to equipment such asan ECG unit for acquiring cardiac electrical information, which may thenbe used by the controller to control various actions related to thecells.

The scenario 402 pertains to treating cells 405 that are external to thebody 406 and/or treating cells 407 that are in a reservoir in the body406 or in the body 406. According to the scenario 402, actions such asdrug administration 410, feeding 420 and conditioning 430 may occur.Various arrangements B, C, D, E and F are shown as being associated withscenario 402. Arrangements B and C are described above.

In arrangement D, a patient has an implanted device that may include acell reservoir. The implanted device may treat cells in a cell reservoiror may treat cells that are not in a reservoir but rather located withina target region of the body such as the myocardium. The implanted devicemay include various features of the device 200 of FIG. 2.

In arrangement E, a patient has two implanted devices whereuni-directional or bi-directional communication may occur. One devicemay be the implanted device described with respect to arrangement Bwhile the other device may include a cell reservoir or features to treatimplanted cells that are not in a reservoir. Thus, at least one of thedevices in arrangement E is capable of delivering drugs 410, nutrients420 and/or conditioning 430 cells.

In arrangement F, a clinician examines a patient and then uses aprogrammer to program an implanted device that can treat cells implantedin the patient whether in a reservoir or not. The programmer includesfeatures for wireless communication with an implantable device capableof treating cells and optionally including a cell reservoir.

The scenario 403 pertains to treating cells 407 that are in a reservoirin the body 406 or in the body 406. According to the scenario 403,actions such as drug administration 410, feeding 420 and conditioning430 may occur. Various arrangements D, E and F are shown as beingassociated with scenario 403, these arrangements are described above.

According to FIG. 4, various arrangements are possible for treatingcells. An exemplary device, devices or a system may be capable oftreating cells external to the body (scenario 401), capable of treatingcells external to the body and internal to the body (scenario 402) orcapable of treating cells internal to the body (scenario 403). Anexemplary device, devices or a system may be capable of injecting one ormore chemicals (e.g., drugs, etc., for purposes other than thosedirectly related to treatment of implanted cells) or injecting cellsinto a patient, for example, as described with respect to FIG. 3 (cellinjection 340). The device 200 of FIG. 2 may be suitably configured tooperate according to any of the scenarios of FIG. 4.

An exemplary device may be capable of operating according to one or moreof the scenarios 401, 402, 403. An exemplary device may be implantable,partially implantable, connectable to implantable or partiallyimplantable components, or completely external, yet optionallyconfigured to sense information or otherwise acquire information (e.g.,ECG/EGM information 350 and/or other information 360). In general, anexemplary device acts at least in part on the basis of sensed and/oracquired information.

FIG. 5 shows an exemplary scenario 500 for pumping media using ECGand/or EGM information. An exemplary device 501 includes circuitry 512,control logic 514, a media reservoir 592 and a pump 595 configured topump media from the media reservoir 592 via a connector port 597. Whilethe circuitry 512 of the device 501 may be capable of sensing cardiacelectrical activity, in the example of FIG. 5, the circuitry 512 allowsfor acquisition of an EGM from an implantable pacing device 502 and/orfor acquisition of an ECG from an ECG unit 504.

According to an exemplary method 550, the device 501 acquiresinformation in an acquisition block 552, detects one or more events in adetection block 554 and activates the pump 595 in an activation block556. A specific example detects end of a T wave to activate the pump andthen deactivates the pump prior to a QRS complex. A pump activation time(Δ_(Pump)) may depend on the amount of matter to deliver to a particularsite or may depend on the heart being in a fairly relaxed state.Regarding the latter, the pump may operate more efficiently when pumpingmedia into relaxed tissue as opposed to contracted tissue. Where cellsare injected, such a method may increase retention of injected cells.

In general, dispersion, uptake, metabolism of pumped matter is ofinterest. Hence, pumped matter may include a contrast or tracking agentthat allows for visualization or tracking the matter whether the matterincludes cells, nutrient medium, drugs, etc. An exemplary methodoptionally delivers a contrast or tracking agent prior to delivery ofother matter to understand how the latter delivered matter may disperseor be retained.

The exemplary method 550 may be used in conjunction with the method 110of FIG. 1. For example, a conventional approach to injection of cells(e.g., stem cells, progenitor cells, etc.) may use ECG informationand/or EGM information to time injection. An exemplary arrangementincludes a syringe or injector that can sense cardiac electricalactivity and use such sensed information for timing injection of cells.Referring to the exemplary lead 205 of FIG. 2, such a lead may beassociated with an injector where the electrodes 207, 207′ may be usedto sense cardiac electrical activity. Injection of matter (cells orother matter) may occur according to a desired event or activity. Suchan injector may repeatedly and incrementally inject matter, for example,after detection of an R wave, a sensed pacing stimulus, an evokedresponse, etc., optionally after a delay (e.g., 300 ms after detectionof an R wave). Such an injector may allow for impedance measurement todetermine whether the opening(s) are positioned appropriately (e.g., intissue, in fluid, etc.). An injector may include control logic orcircuitry that prohibits injection of matter based on impedance (e.g.,as measured between catheter or lead electrodes, needle electrodes,etc.). The device 200 may operate as an injector that can sense cardiacelectrical activity and/or measure impedance and inject or delivermatter based in part on such sensed or measured information.

An exemplary method may include acquiring cardiac electrical activityinformation, detecting a cardiac event based on the acquired cardiacelectrical information and, based on the event, timing delivery ofmatter to the heart where the matter may be one or more of stem cells,progenitor cells, nutrients and drugs. In such a method, the cardiacevent may be an R wave, a QRS complex, a T wave, a P wave, an evokedresponse, etc. The delivery of matter may occur during diastole and/orsystole (e.g., ventricular diastole and/or ventricular systole). Thedelivery may deliver matter to the myocardium, an epicardial artery,etc.

While the scenario of FIG. 5 uses particular information in an ECG or anEGM, other information may be used depending on the function or purposeof an action. An explanation of various features of an ECG (or EGM)follows with respect to FIG. 6, which shows an ECG 600 for one cardiaccycle. The ECG 600 includes various peaks, segments and intervals, someof which have been mentioned above. While one ECG is shown in FIG. 6,depending on specific features of an ECG acquisition system, multipleplots may be acquired. For example, a multiple lead ECG acquisitionsystem can acquire multiple plots for a single cardiac cycle. Ingeneral, each plot is associated with a different lead configuration andhence shapes and timings of the various peaks, segments and intervalsmay vary from plot to plot.

Most ECG acquisition systems rely on multiple leads. For example, onefairly standard multiple lead ECG acquisition system relies on 7 leadswhile another relies on 12 leads. The standard 7 lead system includesleads labeled I, II, III, aVR, aVL and aVF while the standard 12 leadsystem also includes leads labeled V1 through V6. The labels correspondto surface positions with respect to the body.

Given this brief background on multiple lead ECG acquisition systems,the various components of the ECG 600 are now described. In general,depending on detection technique, etc., a “wave” may be assigned a timeassociated with the beginning of the wave, the end of the wave, a peakamplitude of the wave, etc. Also, in some instances, an R wave may beassigned a time associated with the beginning of the QRS complex.Regardless of the convention used, consistency in detection allows formore accurate assessment of patient condition and/or control oftherapeutic actions (e.g., actions related to cells, etc.).

Various peaks are labeled in FIG. 6. The peak labeled “P” corresponds toa P wave caused by depolarization of the atrial myocardium. A normal Pwave usually has a width of less than about 110 ms.

An interval that is measured from the beginning of a P wave to thebeginning of the QRS complex, is referred to as the PR interval, whichrepresents atrial depolarization plus an AV nodal delay. The PR intervalis typically in a range from about 120 ms to about 200 ms. Where AVconduction is impaired, the PR interval is lengthened (e.g.,first-degree AV block). The PR interval includes the PR segment, whichbegins at the end of the P wave and ends with the onset of the QRScomplex. Elevation of the PR segment may indicate disease such as atrialinfarction or pericarditis. Depression of the PR segment may occur if alarge atrial repolarization wave exists.

While labeled as individual peaks in the ECG 600, the QRS complexrepresents depolarization of the ventricular myocardium. Whiledepolarization of the AV node, His bundle, bundle branches, and Purkinjefibers also occurs, the electrical signals emerging from these cardiacstructures are typically too small in amplitude to be detected byelectrodes on the body surface. A “normal” QRS complex will typicallyhave a width ranging from about 70 ms to about 110 ms.

Various conditions may be determined on the basis of the R wave or Rwave progression in a multi-lead system. For example, an early R wave inleads V1 and V2 having a magnitude as large as those in the next severalleads (e.g., V3, V4, V5) can reflect posterior infarction, lateral MI,right ventricular hypertrophy (RVH), or septal hypertrophy. Alsoconsider a large magnitude R wave in V1, which may indicate RVH,posterior MI, or Wolff-Parkinson-White (W-P-W). A poor R waveprogression, e.g., R waves that do not begin to dominate the QRS complexuntil V5 or V6, may represent infarction or injury of the anterior LV.

Small magnitude R waves in the right precordial leads may be due to leftventricular hypertrophy (LVH), left anterior fascicular block (LAFB),COPD, or MI. LVH causes loss of R wave magnitude from V1-V3 without MI.Loss of R magnitude between V1-V2 or V2-V3 in the absence of LVHsuggests anterior MI.

With respect to the Q Wave, not all leads may record a Q wave. Normal Qwaves typically represent septal depolarization. Q waves should bedistinguished from pathologic Q waves that can indicate myocardialinfarction. A “normal” Q wave is usually present in leads I, aVL, V5,and V6 (left lateral leads) only and has a width of about 4 ms. A smallQ wave may be evidenced in aVF and V5 leads. Lack of a Q wave mayindicate septal fibrosis; whereas, a large Q wave (magnitude), mayindicate myocardial damage, as large, diagnostic Q waves representaltered electrical activity in the myocardium due to transmuralmyocardial damage. Note however that a diagnostic Q wave in V1, aVL, orIII may be present without indicating myocardial damage.

An ST segment commences at the “J point” (end of the QRS complex) andends at the onset of the T wave. The ST segment represents the durationfor which ventricular cells are in the plateau phase (phase 2) of theaction potential (where there is no current flow and thus little, if anytransmembrane gradient). QRS complex width and ST segment also representthe duration of the ventricular absolute refractory period, where theventricles will generally not respond to stimulation. The ST segmentshould be isoelectric with a smooth contour. In instances where it isnot isoelectric, the ST segment may be characterized as ST depression orST elevation.

The QT Interval is a measure of the refractory period during which themyocardium would not respond to a second impulse and it is typicallymeasured from the beginning of the QRS complex to the end of the T wave.Some consider leads V2 or V3 as providing the most accurate QT interval.A basic rule indicates that the QT interval should be roughly less thanhalf the preceding RR interval. QT interval normally varies with heartrate. QT interval may also be affected by width of the QRS complex suchas a bundle branch block, which increases the QT interval. Thus, STinterval may be considered to compensate for a wide QRS complex.

A measure referred to as QT dispersion is determined on the basis of QTintervals from various (or all) ECG leads where the shortest QT interval(QT_(Min)) is subtracted from the longest QT interval (QT_(Max)). Asubstantial difference between these two QT intervals may indicate thatheterogeneous refractoriness exists and that the patient may be athigher risk of cardiac death from development of ventriculartachycardia/fibrillation, especially from any proarrhythmic effects ofantiarrhythmic drugs.

JT intervals may be measured to reflect repolarization. The JT intervalis sometimes used to measure the refractory period in patients treatedwith a Na+ channel blocker antiarrhythmic drugs (e.g., Quinidine,Pronestyl, and other class I agents), which slow depolarization andprolong the QRS complex.

The T wave represents repolarization of the ventricles and the earliestthe ventricles can respond to another stimulus usually coincides withthe apex of the T wave. Shortly after the T wave begins the ventriclesstart to relax (ventricular diastole). Contractile fibers in both atriaand ventricles are relaxed for about 200 ms to about 400 ms, typicallyshorter for higher heart rate. In the ECG 600, the heart is typicallyrelaxed (e.g., “relaxation period”) during the TP interval and theventricles relaxed during the TR interval.

ST deviation and T wave abnormalities are seen with conditions otherthan myocardial ischemia such as a wide QRS complex or secondary toeffects of medications. It is possible to have both primary andsecondary changes (e.g., bundle branch block plus ischemia). In thiscase, the ST segment may appear to normalize because both ST depressionand elevation are occurring simultaneously.

Various exemplary techniques described herein deliver matter when theventricles are relaxed. Referring again to the scenario 500 of FIG. 5,activation of a pump occurs to deliver media during a relaxed period, asindicated by an ECG or an EGM. Contraction and relaxation of the heartare associated with movement of calcium from the extracellular space andfrom the stores in the sarcoplastic reticulum. Contraction occurs whenan action potential causes the influx of calcium and relaxation occurswhen the depolarization ceases and calcium is removed from thesarcomere. An increase in intracellular calcium interacts with the actinbinding site so that cross-bridges can attach and thereby allow forcontraction to take place. In absence of calcium, binding sites arecovered and the fibers relaxed, i.e., no significant overlap of actinand myosin exists.

Contraction and relaxation require energy derived from ATP. For anischemic region, availability of ATP may be limited and the ability toremove calcium impaired, resulting in continued coupling of actin/myosincross-bridges. Thus, muscle in an ischemic region may become stiff andless compliant. Various techniques may deliver matter to a boundary ofan ischemic region, which may be more compliant and more capable ofresponding to therapy. Further, particular therapies aim to repairischemic regions or affect tissue at the boundary of an ischemic region.Such techniques may rely on ECG, EGM or other information to moreeffectively deliver a therapy.

With respect to conditioning cells, EGM/ECG information or otherinformation may be used for timing delivery of electrical energy,mechanical energy, a chemical, etc. For example, FIG. 7 shows anexemplary scenario 700 for conditioning cells using ECG/EGM information.The scenario 700 uses an exemplary device 701 that includes circuitry712, control logic 714, stimulation circuitry 743, a cell reservoir 790and a media reservoir 792. While the circuitry 712 of the device 701 maybe capable of sensing cardiac electrical activity, in the example ofFIG. 7, the circuitry 712 allows for acquisition of an EGM from animplantable pacing device 702 and/or for acquisition of an ECG from anECG unit 704.

According to an exemplary method 750, the device 701 acquiresinformation in an acquisition block 752, detects one or more events in adetection block 754 and activates the stimulation circuitry 743 in anactivation block 757 to condition cells in the cell reservoir 790. Aspecific example detects an R wave to activate the conditioning and thendeactivates the conditioning after expiration of an activation time(Δ_(c)), which may depend on properties of cells, cell density, etc.

As already mentioned, an exemplary device may be implantable, partiallyimplantable, connectable to implantable or partially implantablecomponents, or completely external, yet optionally configured to senseinformation or otherwise acquire information (e.g., ECG/EGM information350 and/or other information 360). Thus, the device 701 may be animplantable pacing device capable of delivering pacing or other cardiacstimulation therapies (e.g., defibrillation, etc.). In such an example,conditioning of cells in a reservoir may occur in a coordinated mannerwith delivery of stimulation energy to a patient's heart. For example,if a pacing therapy calls for delivery of stimulation energy to theright ventricle at a rate of 72 beats per minute, then the device 701may condition cells in the cell reservoir 790 at the same rate or a ratebased at least in part on the pacing therapy rate. Further, where thedevice 701 includes control logic for adjusting pacing rate responsiveto patient activity, then delivery of energy to condition cells in thecell reservoir 790 may also be adjusted.

According to the exemplary method 700, a goal may be to minimize risk ofparoxysmal arrhythmia due to the cells, for example, once implanted intothe myocardium. The exemplary device 701 may therefore provide stem celltherapy to minimize the paroxysmal arrhythmia by electrical pacing. Ifsuch treated cells are implanted, then further treatment may occur. Suchtreatment may include use of electrical pacing where pacing optionallyoccurs at an energy level less than the capture threshold forneighboring myocardium and/or where deliver of such energy occurs duringa refractory period of the neighboring myocardium. Hence, theconditioning may use EGM and/or ECG information to determine arefractory period of neighboring myocardium and then use thisinformation to activate conditioning of implanted cells.

Where a patient is fitted with an implantable device for cardiac pacingtherapy, an exemplary method may include calling for delivery of anextra-stimulus. For example, such a method may include calling fordelivery of cardiac pacing pulses at a pre-determined rate and callingfor delivery of one or more cell conditioning pulses. In general, thedelivery of the one or more cell conditioning pulses occurs at a timeother than that of a cardiac pacing pulse. Further, any or all of theone or more cell conditioning pulses may have an energy insufficient tocause cardiac capture.

An exemplary method may call for delivery of the one or more cellconditioning pulses at a pre-determined frequency or at a frequency thatdepends at least in part on acquire cardiac information, whetheracquired via sensing by an implantable device that implements the methodor by an external device that transmits the information to animplantable device that implements the method. The frequency may be onceper cardiac cycle or at a greater or lesser frequency.

An exemplary method may call for delivery of cell conditioning pulses toimplanted cells, cells destined for implantation and/or cells producinga therapeutic agent (e.g., drug, etc.). With respect to implanted cells,such cells may be implanted in the myocardium.

As already mentioned, an exemplary method may delivery energy to cellsimplanted in the heart at an energy level less than a capture thresholdof surrounding myocardial tissue or, more generally, at a levelinsufficient to cause cardiac capture. Such a method may includedetermining a cardiac capture threshold prior to calling for delivery ofone or more cell conditioning pulses. Further, such a method may includedetermining an energy for any or all conditioning pulses based at leastin part on a cardiac capture threshold. An exemplary method may call fordelivery of one or more cell conditioning pulses during a myocardial,non-refractory period and/or during a myocardial, refractory period.

As already mentioned, cells may be conditioned in any of a variety ofmanners. FIG. 8 shows an exemplary scenario 800 where mechanicalconditioning of cells occurs based at least in part on ECG informationor EGM information. The scenario 800 uses an exemplary device 801 thatincludes circuitry 812, control logic 814, a mechanical activator 819and a cell substrate 899. The cell substrate 899 generally provides foranchoring of cells, directional alignment of cells, scaffolding of cellsinto macrostructures, etc. The mechanical activator 819 may cause thecell substrate 899 to bend, stretch, shear, vibrate, etc., in a mannerthat promotes beneficial cell behavior. For example, a bendable polymersubstrate may mimic actin-myosin dimension changes of myocardial tissue.The bendable substrate may be operably connected to a mechanicalactivator that deforms responsive to applied current or voltage (e.g.,dissimilar metals circuit, piezoelectric circuit, etc.). The cellsubstrate 899 may be a sponge or other porous structure that can serveas a support for cells. Thus, the mechanical activator 819 may beconfigured to deform such a structure to thereby condition the cells andoptionally increase transport of nutrients and/or waste products.

While the circuitry 812 of the device 801 may be capable of sensingcardiac electrical activity or mechanical activity, in the example ofFIG. 8, the circuitry 812 allows for acquisition of an EGM from animplantable pacing device 802 and/or for acquisition of an ECG from anECG unit 804.

According to an exemplary method 850, the device 801 acquiresinformation in an acquisition block 852, detects one or more events in adetection block 854 and activates the mechanical activator 819 in anactivation block 858 to condition cells associated with the cellsubstrate 899. A specific example detects an R wave to cause themechanical activator 819 to mechanically deform or move the cellsubstrate 899. A wave form for activation may be adjusted based on cellproperties, cell density, etc. In general, the conditioning promotescell properties or behavior for production of chemicals and/or forimplant of such cells.

The device 801 may be external to the body. For example, the device 801may be wearable such that it is in contact with the body to receive heatfrom the body. The device 801 may include circuitry to acquire ECGinformation or other physiological information for use in conditioningcells. The device 801 may receive a signal from an implantable device(e.g., the device 802) when in close proximity to the implantabledevice. Such a signal may simply indicate a pacing rate or detection ofan R wave or other cardiac event, which may, in turn, be used forconditioning cells associated with the cell substrate 899.

As already mentioned, conditioning may promote desirable cellproperties, behavior, etc. FIG. 9 shows an exemplary method 900 forconditioning cells and deciding if such conditioning has promoteddesirable cell activity. The method 900 commences in an acquisitionblock 904 that acquires information such as ECG, EGM or otherinformation. A conditioning block 908 uses the acquired information tocondition cells, for example, via administration of a drug, delivery ofelectrical energy, mechanical deformation, etc. In the example of FIG.9, the conditioning aims to promote certain desirable cell activity thatmay be sensed by a sense block 912. The sense block 912 may senseelectrical activity of the cells, properties of the cells, behavior ofthe cells responsive to conditioning, etc. The sensing may use sensorsor circuitry associated with a device (e.g., connected to a cellreservoir, a flow path, etc.) or may use a sample from a device foranalysis by another device. For example, a port such as ports 291, 293,296 of the device 200 of FIG. 2 may be used to acquire a sample from acell reservoir, a nutrient reservoir, a flow path, etc.

After sensing, the method 900 enters a decision block 916 that decidesif the sensed cell activity is OK, i.e., indicative of desirableactivity. If the decision block 916 decides that the activity is OK,then the method 900 continues in a cell ready block 920, which indicatesthat the cells are ready for implantation, production of desirablechemicals, etc. (see, e.g., the methods 110, 120 of FIG. 1 and variousother methods). If the decision block 916 decides that the cells are notready, then the method 900 may continue at the acquisition block 904 forfurther conditioning or other action may occur (e.g., administration ofnutrients, termination of cells, etc.).

With respect to sensed cell activity, conditioning may aim to achieve acertain level of cell contractility. Thus, sensing may occur duringdelivery of a stimulus where the sensing can determine how the cellscontracted. Such sensing may monitor fluid composition or mechanicalaction (e.g., force, shear, motion, etc.). A piezoelectric sensor may beused to measure force exerted by cells (e.g., a layer of cells or othermulti-cellular structure).

Conditioning may aim to control growth and alignment of cells. In suchan example, the sensing may sense impedance or other electricalproperties that vary with respect to cell alignment. For example, if thecells are not aligned, then a high resistance to current may exist alongan axis of a cell reservoir; whereas, aligned cells may exhibit lessresistance to current along the axis. In another example, resistance tocurrent may be measured along more than one axis. Where a low resistanceoccurs along one axis and a high resistance occurs along another axisthen the cells may be considered aligned along the low resistance axis.

The exemplary method 900 may apply to cells already injected into thebody (e.g., into the myocardium) such as in the method 110 of FIG. 1. Insuch an example, the cell ready block 920 may simply indicate that nofurther conditioning is required for the already injected cells. Wherecells are already injected, the conditioning may include generation ofan electro-magnetic field at or near the site of injection or theresting site of the cells (e.g., as determined using imaging or othertechniques). As already mentioned, the lead 205 includes electrodes 207,207′ capable of generating an electro-magnetic field. Such a field mayaim to control the effect of intrinsic or paced activity on the injectedcells by enhancing, diminishing or otherwise altering the localenvironment. For example, as the outer or lateral wall of the leftventricle experiences significant stress, delivery of stimulation energyor generation of a field in a region where cells have been injected maypromote growth, retention of cells, etc. Where delivery of electricalenergy occurs to or near a site where cells have been injected, deliveryof electrical energy may occur during a refractory period of the heartto avoid capture of the heart or other undesirable effects.Alternatively, or in addition to, amplitude or duration of anyelectrical energy delivered may be adjusted to be less than a capturethreshold of the heart.

FIG. 10 shows an exemplary method 1000 for delivery of matter such asnutrients, cells, drugs, etc. The method 1000 commences in anacquisition block 1004 that acquires information. The information mayinclude information related to patient physiology such as electricalactivity of the heart and may include information related to a therapy,for example, a dose of a drug or a number of cells to inject.

The method 1000 continues in a determination block 1008 that determinesappropriate parameter values for a delivery cycle to deliver matter. Forexample, the delivery cycle may call for delivery of a certain number ofcells using a solution having a certain cell density. The determinationblock 1008 may determine a number of individual injections required fora delivery cycle to achieve the number of cells. Further, each injectionmay be timed to a cardiac cycle where timing of an individual injectionoccurs during a relaxation period of the heart (e.g., based on T wave,etc.). The determination block 1008 may consider retention of matter ata particular delivery site, diffusion of matter, concentration ofmatter, etc., in an effort to optimize delivery and effectiveness of thedelivered matter.

Once the parameter values have been determined, the method 1000 deliversthe matter via a delivery block 1012. The delivery block 1012 mayoperate to deliver matter over a certain number of cardiac cycles wheredelivery of matter may occur every cardiac cycle or according to someother basis (e.g., every 10th cardiac cycle, etc.). After delivery ofthe matter, the method 1000 continues in a next step(s) block 1016,which may take any of a variety of actions such as returning to theacquisition block 1004 to acquire information that may help evaluate theeffectiveness of the delivered matter.

The exemplary method 1000 may include acquiring cardiac electricalactivity information, detecting a T wave and, based on the detecting,calling for delivery of matter to the heart wherein the matter comprisesat least one member selected from a group consisting of stem cells,progenitor cells, nutrients and drugs. The detection of the T wave mayallow for delivery during a relaxation period of the heart to improveeffectiveness of the delivery.

FIG. 11 shows an exemplary method 1100 that includes delivery of acardiac pacing therapy and a cell conditioning therapy based at least inpart on a cardiac capture threshold. The method 1100 commences in adetermination block 1104 that determines a cardiac capture threshold,for example, using a conventional capture detection technique (e.g.,search algorithm that uses various stimulation energies or timings,etc.). In a delivery block 1106, the method 1100 delivers pacing therapyat or above the determined cardiac capture threshold. Another deliveryblock 1108 of the method 1100 delivers cell conditioning therapy (e.g.,electrical stimulation of cells) below the determined cardiac capturethreshold. The cells to be conditioned may be implanted in themyocardium or in a reservoir, which may be located proximate to themyocardium. In such a manner, cell conditioning avoids inadvertentcapture of the myocardium.

Various exemplary techniques may aim to control (enhance or reduce)nerve sprouting and hyperinnervation. For example, both radiofrequencyablation and stem cell implantation have been reported to induce nervesprouting and heterogenous sympathetic hyperinnervation. Techniques mayaim to reduce such nerve phenomena (and/or the coexistence of adjacentdenervated and hyperinnervated areas), which, in turn, may reduce riskof arrhythmia.

As already mentioned, various techniques aim to reduce risk ofarrhythmia (less arrhythmogenesis). In various examples, a cardiacpacing device may promote cardiac cell alignment and post-injection cellfunction after injecting stem cells in the myocardium as remodeledcardiac cells are known to align better structurally and exhibit lessarrhythmogenesis.

Various exemplary implantable devices include a reservoir for one ormore stem cell based progenitors and control logic to control injectionof the stem cell progenitors to a particular portion of the body (e.g.,the heart) and/or to control pacing at an injection site to promote celladaptation and cell growth. Such a device may include an indentedfunnel-like injection port for adding medication or other matter afterthe device has been implanted. With respect to delivery of matter, suchdelivery may occur according to a rate controlled by an implantabledevice and/or an external device.

An exemplary system may include a pacing lead that also acts as asyringe needle for delivery of cells or other matter. An implantabledevice may include multiple leads where the leads are configured todelivery energy and/or matter to the myocardium or associated vessel. Insuch a system, a pulse may be delivered via one lead at one time and apulse delivered via another lead at another time. Such times may beassociated with systole or diastole and more specifically may be duringa refractory period or non-refractory period. Each of the pulses may beless than a capture threshold or greater than a capture threshold.

Although exemplary methods, devices, systems, etc., have been describedin language specific to structural features and/or methodological acts,it is to be understood that the subject matter defined in the appendedclaims is not necessarily limited to the specific features or actsdescribed. Rather, the specific features and acts are disclosed asexemplary forms of implementing the claimed methods, devices, systems,etc.

1. A method comprising: acquiring cardiac electrical activityinformation; detecting an R wave; and based on the detecting, callingfor delivery of energy to cells located in a structure outside of themyocardium only during a period time within the QRS complexcorresponding to the detected R wave.
 2. The method of claim 1 whereinthe acquiring comprises acquiring cardiac electrical activityinformation from an implantable device.
 3. The method of claim 2 whereinthe acquiring comprises acquiring cardiac electrical activityinformation from a device configured to acquire ECGs.
 4. The method ofclaim 1 wherein the calling calls for delivery of electrical energysubstantially synchronous with the detected R wave.
 5. The method ofclaim 1 wherein the calling calls for delivery of electrical energy at afrequency based at least in part on the detected R wave.
 6. The methodof claim 1 wherein the calling calls for delivery of electrical energyafter expiration of a delay where the delay commences substantiallysynchronous with the detected R wave.
 7. The method of claim 1 whereinthe calling calls for delivery of mechanical energy substantiallysynchronous with the detected R wave.
 8. The method of claim 1 whereinthe calling calls for delivery of mechanical energy at a frequency basedat least in part on the detected R wave.
 9. The method of claim 1wherein the calling calls for delivery of mechanical energy afterexpiration of a delay where the delay commences substantiallysynchronous with the detected R wave.
 10. The method of claim 1 whereinthe structure comprises a substrate that supports the cells and callingcalls for mechanical activation of the.
 11. The method of claim 1wherein the calling calls for administration of a drug to the cells. 12.The method of claim 1 wherein the calling calls for feeding the cells.13. The method of claim 1 further comprising: sensing cell activity todetermine if cells are properly conditioned; and if cells are properlyconditioned, allowing for implant of the cells into the myocardium. 14.The method of claim 13 wherein the sensing comprises sensing thecontractility of the cells.
 15. The method of claim 13 wherein thesensing comprises sensing an electrical property of the cells thatvarious with respect to cell alignment.
 16. The method of claim 15wherein the electrical property comprises impedance
 17. The method ofclaim 13 further comprising: acquiring cardiac electrical activityinformation responsive to delivery of stimulation energy to themyocardium; determining a capture threshold based at least in part onthe acquired information; and based on the determining, calling fordelivery of electrical energy to cells implanted in the myocardium at anenergy level less than the capture threshold.
 18. The method of claim 17further comprising calling for delivery of a cardiac pacing therapyusing a stimulation energy at or above the capture threshold.
 19. Anapparatus comprising: a structure configured to hold cells outside ofthe myocardium; circuitry configured to acquiring cardiac electricalactivity information; means for delivering energy to the cells; andcontrol logic configured to detect cardiac events within the informationincluding R waves, and to activate and deactivate the delivery means soas to deliver energy to the cells only during a time period within theQRS complex corresponding to the detected R wave.
 20. The apparatus ofclaim 19 wherein the delivery means comprises stimulation circuitryconfigured to deliver electrical energy to the cells.
 21. The apparatusof claim 19 wherein the delivery means comprises a mechanical activatorconfigured to deliver mechanical energy to the cells.
 22. The apparatusof claim 21 wherein the mechanical activator is configured to deform tothereby cause the structure to deform.
 23. The apparatus of claim 19wherein the structure is a cell reservoir.
 24. The apparatus of claim 19wherein the structure is a cell substrate.